William H 'Bill' Gross is the founder of Pacific Investment Management (PIMCO), and the most successful bond trader there is, sometimes known simply as The Bond King.
He is at least as famous as a philatelist however, having completed a collection of all US stamps which have been produced in November 2005.
The new gallery at the Smithsonian's National Postal Museum, which will be named after Gross, is expected to open in 2012.
"Stamp collecting has been such a rewarding and educational hobby for me that I wanted to share the joys of philately in a way that would benefit future generations of students, citizens and scholars," said Mr Gross.
Over 5,000 stamps and related postal objects explaining the first 50 years of US postage stamps will be exhibited permanently, which they never have been before.
There will be a special collection of philatelic rarities called Treasures from the William H Gross Collection for the whole of October in recognition of National Stamp Collecting Month.
This will feature three exceptional pieces from Gross's collection:
Firstly, the July 2 1847 cover with the 10c George Washington stamp. On July 1, the first two US stamps were issued: a 5c stamp depicting Benjamin Franklin and this kind.
The July 2 cover is the earliest use of a US postage stamp known to exist.
Secondly, the Pony Express service cover: Indians captured the man carrying this postal item in Nevada while he was travelling from San Francisco to New York City in 1860. The pony, however, escaped and the letter pouch was recovered two years later on the plains and the item delivered.
Thirdly, a block of four Inverted Jennies: The Inverted Jenny is a 24c 1918 stamp with the Curtiss JN-4 ('Jenny') biplane printed upside-down in the centre. There are just six blocks of four in existence, and they hold a special significance for Gross.
To complete his US collection, Gross needed a 1c Z-grill embossed Ben Franklin stamp of which only two are known to exist.
The owner refused to sell the stamp to Gross at any price, but agreed to swap it for the block of 4 'Inverted Jenny' stamps which Gross had bought earlier in 2005 for $2.97m.
Mr Gross has shown previous generosity with his rare stamp collections, having sold part of his Great Britain collection for $10m to benefit the Dr's without borders charity (A collection that he spent $2.5m assembling).
That collection included an example of the Tyrian Plum, one of Britain's rarest stamps.
At the time Mr Gross commented "Four times profit, it's better than the stock market."
Mr Gross's new gallery should inspire a whole new generation of Americans and bring them into the field of stamp collecting.
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